Material and process for making phonograph records



I as

il atented Jan. 19, 1932 ADOLF HAWERLANDER, OF NEW YORK, N. Y.,ASSIGNOR, BY MESNE ASSIGNMENTS, TO DURIUM PRODUCTS CORPORATION, ACORPORATION OF DELAWARE MATERIAL AND, PROCESS FOR MAKING PHONOGRAPHRECORDS No Drawing.

Heretofore in the manufacture of phono-v lle graph records, of the typeformed from materials of dissimilar characteristics, such as laminatedrecords and records made with cardboard cores, and as distinguished fromthe solid stock record, perhaps the most se- 25 rious problemencountered has been that of a successful joinder between several unlikematerials comprising the record. Such troubles have been due largely tothe varying effect of.

temperature and moisture changes on these unlike materials.

The rate of expansion and contraction for a given change in temperature,forinstance,

varies in a fibrousmaterial. such as cardboard. and in the usual kindsof coating material used to surface the cardboard and take the recordimpression. Again. moisture or humidity conditions in the atmospherefrequently are responsible for separating these unlike materials, orblistering, or otherwise giving an uneven surface without sulficientdurability for proper wear during normal use. These have always beenmost serious problems in the manufacture of a cardboard record. They arehere solved for the first time through the invention of a suitablematerial, which eliminates these troubles, andtheprocess ofcompoundingsuch material and applying it to a special fibrous disk.

Most present-day records are made from thermoplastic material, eitherused throughout the record orconcentrated upon its surface. Suchmaterial necessarily contains shellac, which is expensive, and has other(lisadvantages in use.

The present invention more especially comprises a phenol condensationproduct particularly adapted for use as a molding surface for phonographreeords to receive and carry the tone grooves.

Application filed 0ctober 7, 1927. Serial No. 224,770.

Another feature of the present invention resides in the specialadaptability of the particular phenol condensation product hereindisclosed 'to form an intimate bond with a fibrous or paper body for usein manufacturing phonograph records.

This coating material has many additional advantages, such as increasedhardness, minimum abrasion or wear of the playing needle, and properacoustical properties. Also, it is wholly, or almost wholly.transparent, permitting the printing of the cardboard core to be legiblethrough the record recorded in this material which covers it.

In compounding, the ingredients used in the manufacture. of this coatingmaterial, a 40% solution of formaldehyde is used. The first step in theprocess of mixing the ingredients is to properly and closely andsemi-permaneatly unite the formaldehyde solution with linseed oil. Theproportions which have so far given best results are 1000 cubiccentimeters of the formaldehyde solution, and 400 cubic centimeters ofraw linseed oil. These two ingredients in the proportions named arefirst mixed in a homogenizing apparatus as described and illustrated inthe patent to Otto Nielsen, Number 1,654,268, patentedDecember 27, 1927.this mixing apparatus and process resulting in a very close and more orless permanent joinder of these two usually-unmixable ingredients.

This formaldehyde-oil homogenization is strained, and then dissolvedwith about 1000 grams of resoreinol and then, with reasonableeelerity,-brought up to a temperature of 30 centigrade approximately. 7

A solution is next made by dissolving some 10 grams of sodium hydroxidein 50 to 75 cubic centimeters of, the 40% solution of formaldehyde,which is brought to boiling temperature, and cooled off to approximately30 centigrade.

The fornialdehyde-oil-resorcinol solution is brought from the mixing orhomogenizing apparatus from its starting temperature of approximately 30Centigrade to a final temperature of about 80 centigrade very slowly, atthe same time adding drop by drop, the sodiumv hydroxide formaldehydesolution.

The combined solution is then cooled ofi with considerable celerity,again to about 30 centigrade.

The varnish is now ready to be used.

The condensity of this varnish may be varied by going below or above thefinishing temperature of centi 'rade, also by the addition of softeningor filling material, such as shellac, lampblack, or (and) china clay.

In use, the finishing temperature of 80 centigrade with its suddencooling to 30 centigrade represents the correct temperature range whenthe pressing matrices are heated to a temperature of about 180centigrade and the record is pressed at a rate not exceeding 1 secondfor the pressing operation. Should these main conditions for pressing bevaried, the temperatures. would have to be varied to correspond so thatthe proper condition of the varnish coating would apply for any new conditions of pressing.

During the operation of pressing the record, the linseed oil from thesolution, which has been thoroughly but temporarily mixed into theformaldehyde and the other ingredients, through the action of thehomogenizing apparatus, is forced out of the solution and thoroughlyimpregnates the cardboard disk, thus automatically treating the diskboth to make it impervious to moisture and to carry with the oil certainof the other ingredients to thoroughly impregnate the disk material tofurnish a complete joinder between the coating and the disk itself. Thisresults in a unified record structure free of the defects common to suchlaminated or builtup records, such as air bubbles, separation of thecoating from its back stock, and the breaking of the needle through thecoating into the fibrous back stock.

A record of this type may be pressed in multiple in a high-speed pressof the printing-press type from a continuous wide sheet of the fibrousor cardboard material, the individual records afterwards being cut fromthe sheet, thus assuring very rapid production of the record. Thecoating material has been found to be very hard and durable and withoutexcessive scratch on the surface when the record is being played. Thecoating is applied to the flexible cardboard sheet in a thicknessslightly greater than the depth of the standard phonograph groove, whichis about three thousandths of an inch.

It is to be understood that the present disclosure is for the purpose ofillustration only, and that the invention is not limited thereto. Tothose skilled in the art, many modifications of the invention will bereadily apparent, and it will also be obvious to such skilled personsthat part of the concept may be used Without other parts thereof, manysuch combinations of the parts readily suggesting themselves. Therefore,it should be, and is to be distinctly understood that for a definitionof the limitations of the invention, reference must be had to theappended claims.

Having now described the invention, what is claimed as new and for whichLetters Patent of the United States is desired is:

1. The process of compounding the ingredi ents for a sound record,comprising the steps of thoroughly mixing a formaldehyde solution andlinseed oil, dissolving the resulting solution with resorcinol, mixingsodium hydroxide with a formaldehyde solution and applying the resultingmixture. drop by drop, to the former'mixture, and then cooling thecombination mixture from its mixing temperature of approximately 80centigrade to 30 Centigrade.

2. The process of producing a heat and pressure hardening condensationproduct comprising making a solution of a vegetable oil, formaldehyde,and resorcinol; slowly adding a'solution of sodium hydroxide andformaldehyde, and cooling the resulting liquid.

Signed at New York, in the county of New York and State of New York,this 5th day of October, A. D. 1927.

ADOLF HAVVERLANDER.

